There is a need for introducing nucleic acids, such as DNA or RNA for silencing a target gene, into plants, where the methods are scalable so as to be practical for use in multiple plants, such as plants in a greenhouse or growing in a field. Most methods of introducing a nucleic acid for gene suppression are cumbersome and therefore generally of practical use only on individual plants in the laboratory or other small-scale environments. For example, “gene gun” or “biolistic” methods use gold or tungsten particles typically of 0.5 to 2 micrometers in size and coated with DNA or RNA that has been precipitated onto the particles; the particles are discharged using a “gene gun” powered by a gas at high pressure (typically hundreds to thousands pounds per square inch) onto a plant held in an evacuated chamber. More recent biolistic methods using equipment such as the Helios® gene gun (Bio-Rad Laboratories, Inc.) use lower pressures (in the hundreds pounds per square inch) but still require the use of helium gas as a propellant and use of gold or tungsten particles typically of 0.5 to less than 2 micrometers in size that must be pre-coated with a nucleic acid; furthermore, each plant must be treated individually and individual “cartridges” containing the particles must be prepared for each treatment. These limitations make the gene gun approaches inconvenient for true scalability for treating large numbers of plants such as in greenhouse and field use.
The present disclosure is related to various methods and compositions for introducing nucleic acids into a plant, where the methods are scalable and adaptable for use in multiple plants, and even for agricultural use in plants growing in a field.